Piston.



938 ,48 1 Patented Nov. 2, 1909.

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Witnesses: Inventor UNITED STATES.. PATENT OFFICE.

THOMAS HALL, OF RIDGWAY, PENNSYLVANIA, ASSIGNOR TO RIDGWAY DYNAMO & ENGINE COMPANY, OF RIDGWAY, PENNSYLVANIA.

PISTON.

Specification of Letters Patent.

Application filed April 21, 1909.

Patented Nov. '2, 1909. Serial No. 491,280.

To all whom it may concern:

Be it known that I, THOMAS HALL, a subject of the King of Great Britain, residing at Ridgway, Elk county, Pennsylvania, have invented certain new and useful Improvements in Pistons, of which the following is a specification.

This invention, pertaining to improvements in pistons for engines, pumps etc., will be readily understood from the following description taken in connection with the accompanying drawing in which Figure l is a front elevation, part vertical section, of a piston embodying my present construction, while Fig. 2 is a side elevation, part vertical section, of the same.

In the drawing l, indicates the piston body, of usual disk form: 2, the rod-hole therein: 3, an annular series of segmental cavities in the piston body each cavity extending radially from the hub to the rim of the piston body: 4, a port extending outw wardly from each of the cavities 3 entirely through the rim of the piston: 5, radial partitions extending from the hub to the rim of the piston and separating the segmental cavities: 6, circumferential projections from the outer ends of the partitions 5 at the rim of the piston: 7, packing rings, of common type, seated in grooves in the periphery of the piston: 8, a hoop disposed within a central circumferential groove in the body of the piston and resting on the outer ends of the partitions and on the circumferential projections 6 therefrom and on shoulders at the side margins of the ports 4: 9, a hoop of comparatively soft metal disposed within the central groove of the piston around hoop S, the groove being preferably dovetailed: l0, the side margins of the ports 4, formed by the inward project-ions from the sides of the piston-body and extending circumferentially between the projections 6: and 11, ports extending through the radial partitions.

Assume, for the instant that ports 11 are absent, the segmental chambers 3 in such case being disconnected from each other. In constructing the piston the segmental chambers are formed by cores, and in the above assumed construction, each individual core would be supported by a print extending outwardly from its individual peripheral port 4, there being as many of these ports as there are segmental chambers. But when the ports l1 through the radial partitions are provided then contiguous segmental cores may give each other support and it no longer becomes necessary to provide a peripheral port 4 for each of the segmental chambers, indeed, it is suiiicient if only enough of the peripheral ports be provided to permit of the proper support and proper removal of the core or cores. It will be understood that the radial partitions are merely strengthening elements, there being no special reason, aside from mere strength, for dividing the interior of the piston up into individual chambers.

In the drawing the rings 7 and 9 are shown as projecting beyond the periphery of the piston, but this is a mere matter of preference, a flush construction being preferable under some conditions. It will be understood that the hoop 8 furnishes a means for closing the peripheral ports and fur nishing a backing for the soft-metal hoop 9, a construction permitting of large peripheral ports in the piston, and of a comparatively thin soft-metal hoop. There the pen ripheral ports are few, or small, or where the hoop 9 is of sufficient thickness or hardness, the inner hoop 8 may be dispensed with. My preference is to employ the hoop 8, formed by bending a strip of metal to suitable size and springing it into the groove of the pis ton. The soft-inetal hoop may then be placed, in any suitable manner, my preference being to cast this hoop in segments which are placed in the groove and then peened to tightness, the exterior of the softinetal hoop being then properly turned. No machine work is necessary in the groove containing hoops 8 and 9.

In the particular form of piston chosen to illust-rate my invention, the peripheral ports of the piston are closed by a hoop centrally disposed and flanked by packing rings, this being the preferred construction. But there may obviously be more than one circumferential line of peripheral ports with covering hoops, and the packing rings, if employed, may be intermediate instead of flanking elements.

l. A piston having a peripherally grooved hollow body provided with one or more ports through its rim and placing the groove in ton, a hoop disposed in the base of the groove over the port or ports therein, and a covering-ring of softer material than the hoop disposed in the groove exterior to said hoop, l

combined substantially as set forth.

2. A piston having a peripherally grooved hollow body provided with one or more ports through its rim and placing the groove in communication with the interior of the piston, a hoop disposed in the base of the groove over said port or ports, and a ring formed of segments of softer vmaterial than the hoop secured in said groove over said hoop, conibined substantially as set forth.

3. A piston having a peripherally grooved hollow body provided with one or more ports through its rim and placing the groove in communication with the interior of the piston, said port or ports being provided with inwardly projecting side margins, a circumferential series of radial partitions dividing the hollow of the piston into segmental chambers communicating with said port or ports, and a covering-ring disposed in the groove of the piston, closing said ports and resting on the side margins thereof, combined substantially as set forth.

4:. A piston having a peripherally grooved hollow body provided with one or more ports through its rim kand placing the groove in communication with the interior of the piston, said port or ports being provided with side margins projecting inwardly from the walls of said groove, and a covering-ring disposed in said groove and resting on said inwardly projecting side margins, combined substantially as set forth.

5. A piston comprising a peripherally grooved hollow body provided with ports placing the groove in communication with the interior of the piston, a covering ring disposed in said groove and covering said ports, and packing rings carried by the body on opposite sides of the covering ring.

6. A piston having a peripherally grooved hollow body provided with internal radial partitions, the rim of the body having ports therein locatedat points between the partitions and establishing communication between the groove and interior of the piston, and a covering ring disposed in the groove covering the ports therein.

7. A piston comprising a hollow body provided with a peripheral groove with ports in said groove leading to the interior of the piston, said ports having side margins projecting inwardly from the walls of the groove,a backing hoop disposed in said groove and resting on said inwardly projecting side margins, and a segmental ring secured in vsaid' groove over the hoop. 1

THOMAS HALL. lVitnesses:

CHARLES C. SHOLLENBERGER, LEwrs J. A. LEssER. 

